Sushi, from nigiri to temaki, is growing in popularity with restaurants popping up in most major cities. Sushi is the name given to a Japanese preparation using vinegared rice combined with different ingredients, of which the most common is uncooked seafood. Uncooked seafood carries risks due to many fish having parasites. Most cooking methods destroy the parasites, drawing a distinction between the safety of raw fish and cooked fish. Raw fish can be rendered safe if it is frozen before it is sold to consumers (a practice recommended by the European Union); the risks arise where freezing does not happen.
The latest warning comes from medics who have written to the journal British Medical Journal Case Reports (article: “Anisakiasis: a growing cause of abdominal pain!) The in the article the doctors state that sushi’s growing popularity in the West appears to be linked to a rise in parasitic infections. In the article the medics cite various cases on parasites contracted from eating sushi. One example is with Anisakiasis, which is a parasitic disease caused by anisakid nematodes (a type of worm) that invades the stomach wall or intestine of humans. The case involved a 32-year-old man, in Lisbon, who was found to have the parasite larvae on his gut lining.
With this disease, within a few hours of ingestion, the parasitic worm attempts to burrow though the intestinal wall. Since it cannot penetrate it, it becomes stuck and eventually dies. However, the presence of the parasite triggers an immune response. Here the immune cells surround the worms, forming a ball-like structure that can block the digestive system, causing severe abdominal pain, malnutrition and vomiting.
In addition to the Lisbon case, The Guardian describes a Spanish study that reported 25 cases of the same parasitic condition over a three year period.
